Turbine blades for heavy duty gas turbines are required to operate reliably at high speeds in a hostile environment. This is particularly true for end-stage turbine blades, which tend to be very long, placing considerable strain on the blades. Existing blade designs can provide damping of vibrations, lightweight design, or minimal over-tip leakage flow, but struggle to provide good performance in all of these areas at once, especially in end-stage turbine blades where the centrifugal forces are highest and the need for stiff and lightweight designs is particularly acute. As a result, it has been appreciated that the design of turbine blades could be refined to provide improved turbine blade performance, particularly in end-stage turbine blades.